Sgt. Calvin Gibbs of Billings, Montana is among five soldiers from the Army's Joint Base Lewis-McChord charged with taking part in three thrill kills in Afghanistan in 2010 in a case that includes allegations of widespread drug use, the collection of body parts and photos of the U.S. soldiers holding the Afghan bodies like hunter's trophies.

Three soldiers have already pled guilty. Gibbs, the squad leader, is accused of masterminding the murders, in which the soldiers allegedly set up scenarios to kill unarmed civilians and then planted weapons to make the deaths appear justified. He could face life in prison if convicted. Jury selection in the trial, which is being held in a military courtroom south of Seattle, began Friday.

In a confession taped in May 2010 and obtained by ABC News, one of the soldiers admitted the team's role in the murders, but told Army investigators that Gibbs, his unit's "crazy" sergeant, had hatched the plan.

"He just really doesn't have any problems with f---ing killing these people," Jeremy Morlock told military investigators during an interview videotaped at Kandahar Airfield, Afghanistan as he laid out the scenario he said the sergeant used to make it seem the civilians were killed in action.

"And so we identify a guy. Gibbs makes a comment, like, you know, you guys wanna wax this guy or what?" Morlock said." And you know, he set it up, like, he grabbed the dude."

Morlock said that killing people came "too easy" to Gibbs.

The corporal said Gibbs gave orders to open fire on the civilian at the same time Gibbs threw a hand grenade at the victim.

"He pulled out one of his grenades, an American grenade, you know, popped it, throws it, tells me where to go to whack this guy, kill this guy, kill this guy," Morlock told the investigators.

Morlock said Sergeant Gibbs carried a Russian grenade to throw next to the body of the dead Afghan, to make it seem he was about to attack the American soldiers.

The corporal said he opened fire as directed, fearful of not following Gibbs' orders.

"It's definitely not the right thing to do," Morlock told the investigators. "But I mean, when you got a squad leader bringing you into that, that type of real, that mindset, and he believes that you're on board with that, there's definitely no way you wanted him to think otherwise."

The investigator asked Morlock, "Because you felt maybe the next shot might be coming your way?"

"You never know. Exactly," answered Morlock. "I mean Gibbs talked about how easy it is, people disappear on the battlefield all the time."

A lawyer for Gibbs declined to comment. In March, Morlock pled to three counts of premeditated murder and was sentenced to 24 years in prison.